A Wireless Local Area Network (WLAN) is a wireless computer network that links two or more devices using a wireless distribution method, often spread-spectrum or Orthogonal Frequency Division Multiplexing (OFDM) radio, within a limited area such as a home, school, computer laboratory, or office building. This gives users the ability to move around within a local coverage area and still be connected to the network, and may provide a connection to the wider Internet. Most modern WLANs are based on IEEE 802.11 standards, marketed under the W-Fi brand name.
All components that may connect into a wireless medium in a WLAN are referred to as STAtions (STA). Wireless stations fall into one of two categories: wireless Access Points (AP) and clients.
APs, normally wireless routers, are base stations for the wireless network. They transmit and receive radio frequencies for wireless enabled devices to communicate with. Wireless clients may be mobile devices such as laptops, personal digital assistants, IP phones and other smartphones, or fixed devices such as desktops and workstations that are equipped with a wireless network interface.
A Basic Service Set (BSS) is a set of all stations that can communicate with each other.
IEEE 802.11ah is a wireless networking protocol that is an amendment of the IEEE 802.11-2007 wireless networking standard. It utilizes sub 1 GHz license-exempt bands to provide extended range W-Fi networks, compared to conventional Wi-Fi networks operating in the 2.4 GHz and 5 GHz bands. It also benefits from lower energy consumption, allowing the creation of large groups of stations or sensors that cooperate to share the signal, supporting the concept of the Internet of Things (IoT).
Many important use cases for 802.11ah involve low duty cycle, battery driven STAs, where power efficiency is paramount. For this reason, a new sensor type STA has been introduced in 802.11ah. These devices are expected to operate for several years powered by small batteries.
Weightless is a radio access standard intended for Machine-to-Machine (M2M) communication and IoT applications. The Weightless-N standard, designed to operate in the 900 MHz Industrial, Scientific and Medical (ISM) bands, is currently under development and is expected to be finished in 2015. Weightless-N is expected to provide coverage in the order of tens of km. The carrier bandwidths are expected to be very narrow, most likely less than 1 kHz.
The coverage of 802.11ah is less than 1 km. Therefore, in regions where Weightless-N and 802.11ah networks co-exist, it is likely that many 802.11ah BSSs will be located within the area of coverage of one Weightless-N base station, as illustrated in FIG. 1. This means that Weightless narrowband interference will impact the performance of 802.11ah networks. For example, strong narrowband interference causes the channel estimates in the affected subcarriers to be very noisy.